The present invention relates to a method and to a machine for disposing of a sticky sheet. More particularly, the present invention relates to a method and a machine for disposing of a used stencil sheet which has been used for stencil printing and which is sticky with stencil printing ink.
Various rotary stencil printing devices are presently known in the art. In a typical such rotary stencil printing device a stencil master, which is of the form of a flat sheet pierced with apertures whose shapes define characters, figures, etc. which it is desired to reproduce, is fixed around the cylindrical outer periphery of a printing drum. Ink is supplied from within the printing drum through holes or the like in the outer peripheral surface thereof to the radially inner side of the stencil master, and this ink passes through the above apertures to the radially outer side of the stencil master. The printing drum is rotated, and paper or the like on which it is required to form printed impressions is brought into contact with the radially outer surface of the stencil master fixed around the periphery of the rotating printing drum. Accordingly, printed copies are produced in as many numbers as desired.
In such a conventional rotary stencil printing device, after printing from a particular stencil master sheet has been completed, it is of course required to remove the stencil sheet from the printing drum, and it is subsequently necessary to dispose of the used stencil sheet, which at this time is moist and sticky with the remnants of the ink which has been used for printing. Conventionally, both the removal operation for the used stencil sheet, and the disposal operation thereof, have been carried out by hand by the operator of the rotary stencil printing device, but this is an unsatisfactory method. Both of these operations are troublesome and time consuming, and the used stencil sheet which is sticky with printing ink is extremely messy, and accordingly there is a great danger that a human operator performing these operations by hand will become soiled with the printing ink; it is also quite likely that the clothes of the operator will become dirty with the printing ink.
With regard to the operation of peeling off the used stencil sheet from the outer cylindrical peripheral surface of the printing drum, a desirable and convenient means for doing this is for one edge of the stencil sheet which extends along the direction of the generatrices of the printing drum to be first removed from the surface of the printing drum, and then for this edge of the stencil sheet, perhaps via a lug or the like provided thereon, to be pulled in the direction away from the printing drum along a line which is tangential to the surface of the printing drum, while the printing drum is rotated in an appropriate direction. In this way, the stencil sheet is progressively unwrapped from around the outer periphery of the printing drum, against the sticky and viscous effect provided by the printing ink which is present between the stencil sheet and the printing drum. A technique for performing this operation automatically has been proposed in Japanese Utility Model Application No. 179596 which was filed on Dec. 24, 1979 in the Japanese Patent Office, by Riso Kagaku Corporation.
With regard to the operation of disposal of the sticky stencil sheet after it has been peeled away from the outer periphery of the printing drum, prior art techniques for doing this, which have involved manual intervention by the operator of the machine, have been very unsatisfactory. It takes quite a long time to dispose of such a sticky stencil sheet by hand, especially if the operation is to be performed cleanly, without soiling the operator. Further, if the used sticky stencil sheet is discarded, in the form in which it has been removed from the rotary printing drum, into a wastepaper basket, special purpose disposal box, or disposal bag, then, because the used stencil sheet is considerably bulky, the box or bag quickly becomes full. On the other hand, crumpling up or folding the sticky stencil sheet into a compact form while it is sticky with printing ink, by hand, is a very unattractive procedure for the operator of the machine, and will inevitably soil the operator. In practice, therefore, according to prior art disposal methods, the box or bag which is being used for disposal of sticky used stencil sheets quickly becomes full, and this presents the problem that inevitably frequent cleaning or exchange of this box or bag will be required.